<!DOCTYPE html>
<html>

<head>
  <style>
    body {
      width: 300px;
      padding: 10px;
      font-family: Arial, sans-serif;
    }

    .switch {
      position: relative;
      display: inline-block;
      width: 60px;
      height: 34px;
    }

    .switch input {
      opacity: 0;
      width: 0;
      height: 0;
    }

    .slider {
      position: absolute;
      cursor: pointer;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      background-color: #ccc;
      transition: .4s;
      border-radius: 34px;
    }

    .slider:before {
      position: absolute;
      content: "";
      height: 26px;
      width: 26px;
      left: 4px;
      bottom: 4px;
      background-color: white;
      transition: .4s;
      border-radius: 50%;
    }

    input:checked+.slider {
      background-color: #e2231a;
    }

    input:checked+.slider:before {
      transform: translateX(26px);
    }

    .switch-label {
      margin-left: 10px;
      vertical-align: super;
    }
  </style>
</head>

<body>
  <label class="switch">
    <input type="checkbox" id="toggleFloatingWindow">
    <span class="slider"></span>
  </label>
  <span class="switch-label">auto open product viewer</span>
  <script src="popup.js"></script>
</body>

</html>